October 2024 - Linux-stable-mirror

[PATCH v3 2/2] staging: vchiq_arm: Utilize devm_kzalloc() for allocation

by Umang Jain

The struct drv_mgmt 'mgmt' is currently allocated dynamically using kzalloc(). Unfortunately, it is subjected to memory leaks in the error handling paths of the probe() function. To address this issue, use device resource management helper devm_kzalloc(), to ensure cleanup after the allocation. Cc: stable(a)vger.kernel.org Fixes: 1c9e16b73166 ("staging: vc04_services: vchiq_arm: Split driver static and runtime data") Signed-off-by: Umang Jain <umang.jain(a)ideasonboard.com> --- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 7ece82c361ee..8412be7183fc 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -1343,7 +1343,7 @@ static int vchiq_probe(struct platform_device *pdev) return -ENOENT; } - mgmt = kzalloc(sizeof(*mgmt), GFP_KERNEL); + mgmt = devm_kzalloc(&pdev->dev, sizeof(*mgmt), GFP_KERNEL); if (!mgmt) return -ENOMEM; @@ -1397,8 +1397,6 @@ static void vchiq_remove(struct platform_device *pdev) arm_state = vchiq_platform_get_arm_state(&mgmt->state); kthread_stop(arm_state->ka_thread); - - kfree(mgmt); } static struct platform_driver vchiq_driver = { -- 2.45.2

8 months, 3 weeks

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[PATCH v3 1/2] staging: vchiq_arm: Utilise devm_kzalloc() for allocation

by Umang Jain

The struct vchiq_arm_state 'platform_state' is currently allocated dynamically using kzalloc(). Unfortunately, it is never freed and is subjected to memory leaks in the error handling paths of the probe() function. To address the issue, use device resource management helper devm_kzalloc(), to ensure cleanup after its allocation. Fixes: 71bad7f08641 ("staging: add bcm2708 vchiq driver") Cc: stable(a)vger.kernel.org Signed-off-by: Umang Jain <umang.jain(a)ideasonboard.com> --- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index af623ad87c15..7ece82c361ee 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -285,7 +285,7 @@ vchiq_platform_init_state(struct vchiq_state *state) { struct vchiq_arm_state *platform_state; - platform_state = kzalloc(sizeof(*platform_state), GFP_KERNEL); + platform_state = devm_kzalloc(state->dev, sizeof(*platform_state), GFP_KERNEL); if (!platform_state) return -ENOMEM; -- 2.45.2

8 months, 3 weeks

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Re: Patch "Revert "mm/filemap: avoid buffered read/write race to read inconsistent data"" has been added to the 6.6-stable tree

by Baokun Li

On 2024/10/11 8:17, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > Revert "mm/filemap: avoid buffered read/write race to read inconsistent data" > > to the 6.6-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… > > The filename of the patch is: > revert-mm-filemap-avoid-buffered-read-write-race-to-.patch > and it can be found in the queue-6.6 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable(a)vger.kernel.org> know about it. > Hi Sasha, The current patch is a cleanup after adding smp_load_acquire/store_release() to i_size_read/write(). In my opinion stable versions continue to use smp_rmb just fine, no need to backport the current patch to stable. In addition, the current patch belongs to a patch set: https://lore.kernel.org/all/20240124142857.4146716-1-libaokun1@huawei.com/ If the current patch does need to be backported to stable, then the entire patch set needs to be backported or problems will be introduced. All the patches in the patch set are listed below: d8f899d13d72 ("fs: make the i_size_read/write helpers be smp_load_acquire/store_release()") 4b944f8ef996 ("Revert "mm/filemap: avoid buffered read/write race to read inconsistent data"") ad72872eb3ae ("asm-generic: remove extra type checking in acquire/release for non-SMP case") Thanks, Baokun > > commit d87bcb0965636a9b665231560ce147d06a7a18d8 > Author: Baokun Li <libaokun1(a)huawei.com> > Date: Wed Jan 24 22:28:56 2024 +0800 > > Revert "mm/filemap: avoid buffered read/write race to read inconsistent data" > > [ Upstream commit 4b944f8ef99641d5af287c7d9df91d20ef5d3e88 ] > > This reverts commit e2c27b803bb6 ("mm/filemap: avoid buffered read/write > race to read inconsistent data"). After making the i_size_read/write > helpers be smp_load_acquire/store_release(), it is already guaranteed that > changes to page contents are visible before we see increased inode size, > so the extra smp_rmb() in filemap_read() can be removed. > > Signed-off-by: Baokun Li <libaokun1(a)huawei.com> > Link: https://lore.kernel.org/r/20240124142857.4146716-3-libaokun1@huawei.com > Signed-off-by: Christian Brauner <brauner(a)kernel.org> > Signed-off-by: Sasha Levin <sashal(a)kernel.org> > > diff --git a/mm/filemap.c b/mm/filemap.c > index e6c112f3a211f..cd028f3be6026 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2694,15 +2694,6 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter, > goto put_folios; > end_offset = min_t(loff_t, isize, iocb->ki_pos + iter->count); > > - /* > - * Pairs with a barrier in > - * block_write_end()->mark_buffer_dirty() or other page > - * dirtying routines like iomap_write_end() to ensure > - * changes to page contents are visible before we see > - * increased inode size. > - */ > - smp_rmb(); > - > /* > * Once we start copying data, we don't want to be touching any > * cachelines that might be contended:

8 months, 3 weeks

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[PATCH v2 0/2] staging: vchiq_arm: Fix missing refcount decrement in error path for fw_node

by Javier Carrasco

This series refactors some useless goto instructions as a preparation for the fix of a missing of_node_put() by means of the cleanup attribute. Signed-off-by: Javier Carrasco <javier.carrasco.cruz(a)gmail.com> --- Changes in v2: - Refactor vchiq_probe() to remove goto instructions. - Declare and initialize the node right before its first usage. - Link to v1: https://lore.kernel.org/r/20241013-vchiq_arm-of_node_put-v1-1-f72b2a6e47d0@… --- Javier Carrasco (2): staging: vchiq_arm: refactor goto instructions in vchiq_probe() staging: vchiq_arm: Fix missing refcount decrement in error path for fw_node .../vc04_services/interface/vchiq_arm/vchiq_arm.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) --- base-commit: d61a00525464bfc5fe92c6ad713350988e492b88 change-id: 20241013-vchiq_arm-of_node_put-60a5eaaafd70 Best regards, -- Javier Carrasco <javier.carrasco.cruz(a)gmail.com>

8 months, 3 weeks

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[PATCH RESEND v3 3/3] block: fix ordering between checking BLK_MQ_S_STOPPED and adding requests

by Muchun Song

Supposing first scenario with a virtio_blk driver. CPU0 CPU1 blk_mq_try_issue_directly() __blk_mq_issue_directly() q->mq_ops->queue_rq() virtio_queue_rq() blk_mq_stop_hw_queue() virtblk_done() blk_mq_request_bypass_insert() 1) store blk_mq_start_stopped_hw_queue() clear_bit(BLK_MQ_S_STOPPED) 3) store blk_mq_run_hw_queue() if (!blk_mq_hctx_has_pending()) 4) load return blk_mq_sched_dispatch_requests() blk_mq_run_hw_queue() if (!blk_mq_hctx_has_pending()) return blk_mq_sched_dispatch_requests() if (blk_mq_hctx_stopped()) 2) load return __blk_mq_sched_dispatch_requests() Supposing another scenario. CPU0 CPU1 blk_mq_requeue_work() blk_mq_insert_request() 1) store virtblk_done() blk_mq_start_stopped_hw_queue() blk_mq_run_hw_queues() clear_bit(BLK_MQ_S_STOPPED) 3) store blk_mq_run_hw_queue() if (!blk_mq_hctx_has_pending()) 4) load return blk_mq_sched_dispatch_requests() if (blk_mq_hctx_stopped()) 2) load continue blk_mq_run_hw_queue() Both scenarios are similar, the full memory barrier should be inserted between 1) and 2), as well as between 3) and 4) to make sure that either CPU0 sees BLK_MQ_S_STOPPED is cleared or CPU1 sees dispatch list. Otherwise, either CPU will not rerun the hardware queue causing starvation of the request. The easy way to fix it is to add the essential full memory barrier into helper of blk_mq_hctx_stopped(). In order to not affect the fast path (hardware queue is not stopped most of the time), we only insert the barrier into the slow path. Actually, only slow path needs to care about missing of dispatching the request to the low-level device driver. Fixes: 320ae51feed5 ("blk-mq: new multi-queue block IO queueing mechanism") Cc: stable(a)vger.kernel.org Cc: Muchun Song <muchun.song(a)linux.dev> Signed-off-by: Muchun Song <songmuchun(a)bytedance.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> --- block/blk-mq.c | 6 ++++++ block/blk-mq.h | 13 +++++++++++++ 2 files changed, 19 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index ff6df6c7eeb25..b90c1680cb780 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2413,6 +2413,12 @@ void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) return; clear_bit(BLK_MQ_S_STOPPED, &hctx->state); + /* + * Pairs with the smp_mb() in blk_mq_hctx_stopped() to order the + * clearing of BLK_MQ_S_STOPPED above and the checking of dispatch + * list in the subsequent routine. + */ + smp_mb__after_atomic(); blk_mq_run_hw_queue(hctx, async); } EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); diff --git a/block/blk-mq.h b/block/blk-mq.h index 260beea8e332c..f36f3bff70d86 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -228,6 +228,19 @@ static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx) { + /* Fast path: hardware queue is not stopped most of the time. */ + if (likely(!test_bit(BLK_MQ_S_STOPPED, &hctx->state))) + return false; + + /* + * This barrier is used to order adding of dispatch list before and + * the test of BLK_MQ_S_STOPPED below. Pairs with the memory barrier + * in blk_mq_start_stopped_hw_queue() so that dispatch code could + * either see BLK_MQ_S_STOPPED is cleared or dispatch list is not + * empty to avoid missing dispatching requests. + */ + smp_mb(); + return test_bit(BLK_MQ_S_STOPPED, &hctx->state); } -- 2.20.1

8 months, 3 weeks

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[PATCH RESEND v3 2/3] block: fix ordering between checking QUEUE_FLAG_QUIESCED and adding requests

by Muchun Song

Supposing the following scenario. CPU0 CPU1 blk_mq_insert_request() 1) store blk_mq_unquiesce_queue() blk_queue_flag_clear() 3) store blk_mq_run_hw_queues() blk_mq_run_hw_queue() if (!blk_mq_hctx_has_pending()) 4) load return blk_mq_run_hw_queue() if (blk_queue_quiesced()) 2) load return blk_mq_sched_dispatch_requests() The full memory barrier should be inserted between 1) and 2), as well as between 3) and 4) to make sure that either CPU0 sees QUEUE_FLAG_QUIESCED is cleared or CPU1 sees dispatch list or setting of bitmap of software queue. Otherwise, either CPU will not rerun the hardware queue causing starvation. So the first solution is to 1) add a pair of memory barrier to fix the problem, another solution is to 2) use hctx->queue->queue_lock to synchronize QUEUE_FLAG_QUIESCED. Here, we chose 2) to fix it since memory barrier is not easy to be maintained. Fixes: f4560ffe8cec ("blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue") Cc: stable(a)vger.kernel.org Cc: Muchun Song <muchun.song(a)linux.dev> Signed-off-by: Muchun Song <songmuchun(a)bytedance.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> --- block/blk-mq.c | 47 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 34 insertions(+), 13 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index b2d0f22de0c7f..ff6df6c7eeb25 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2202,6 +2202,24 @@ void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) } EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); +static inline bool blk_mq_hw_queue_need_run(struct blk_mq_hw_ctx *hctx) +{ + bool need_run; + + /* + * When queue is quiesced, we may be switching io scheduler, or + * updating nr_hw_queues, or other things, and we can't run queue + * any more, even blk_mq_hctx_has_pending() can't be called safely. + * + * And queue will be rerun in blk_mq_unquiesce_queue() if it is + * quiesced. + */ + __blk_mq_run_dispatch_ops(hctx->queue, false, + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx)); + return need_run; +} + /** * blk_mq_run_hw_queue - Start to run a hardware queue. * @hctx: Pointer to the hardware queue to run. @@ -2222,20 +2240,23 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING); - /* - * When queue is quiesced, we may be switching io scheduler, or - * updating nr_hw_queues, or other things, and we can't run queue - * any more, even __blk_mq_hctx_has_pending() can't be called safely. - * - * And queue will be rerun in blk_mq_unquiesce_queue() if it is - * quiesced. - */ - __blk_mq_run_dispatch_ops(hctx->queue, false, - need_run = !blk_queue_quiesced(hctx->queue) && - blk_mq_hctx_has_pending(hctx)); + need_run = blk_mq_hw_queue_need_run(hctx); + if (!need_run) { + unsigned long flags; - if (!need_run) - return; + /* + * Synchronize with blk_mq_unquiesce_queue(), because we check + * if hw queue is quiesced locklessly above, we need the use + * ->queue_lock to make sure we see the up-to-date status to + * not miss rerunning the hw queue. + */ + spin_lock_irqsave(&hctx->queue->queue_lock, flags); + need_run = blk_mq_hw_queue_need_run(hctx); + spin_unlock_irqrestore(&hctx->queue->queue_lock, flags); + + if (!need_run) + return; + } if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { blk_mq_delay_run_hw_queue(hctx, 0); -- 2.20.1

8 months, 3 weeks

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[PATCH RESEND v3 1/3] block: fix missing dispatching request when queue is started or unquiesced

by Muchun Song

Supposing the following scenario with a virtio_blk driver. CPU0 CPU1 CPU2 blk_mq_try_issue_directly() __blk_mq_issue_directly() q->mq_ops->queue_rq() virtio_queue_rq() blk_mq_stop_hw_queue() virtblk_done() blk_mq_try_issue_directly() if (blk_mq_hctx_stopped()) blk_mq_request_bypass_insert() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_insert_request() return After CPU0 has marked the queue as stopped, CPU1 will see the queue is stopped. But before CPU1 puts the request on the dispatch list, CPU2 receives the interrupt of completion of request, so it will run the hardware queue and marks the queue as non-stopped. Meanwhile, CPU1 also runs the same hardware queue. After both CPU1 and CPU2 complete blk_mq_run_hw_queue(), CPU1 just puts the request to the same hardware queue and returns. It misses dispatching a request. Fix it by running the hardware queue explicitly. And blk_mq_request_issue_directly() should handle a similar situation. Fix it as well. Fixes: d964f04a8fde ("blk-mq: fix direct issue") Cc: stable(a)vger.kernel.org Cc: Muchun Song <muchun.song(a)linux.dev> Signed-off-by: Muchun Song <songmuchun(a)bytedance.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> --- block/blk-mq.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index e3c3c0c21b553..b2d0f22de0c7f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2619,6 +2619,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return; } @@ -2649,6 +2650,7 @@ static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return BLK_STS_OK; } -- 2.20.1

8 months, 3 weeks

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[PATCH] staging: vchiq_arm: Fix missing refcount decrement in error path for fw_node

by Javier Carrasco

An error path was introduced without including the required call to of_node_put() to decrement the node's refcount and avoid leaking memory. If the call to kzalloc() for 'mgmt' fails, the probe returns without decrementing the refcount. Use the automatic cleanup facility to fix the bug and protect the code against new error paths where the call to of_node_put() might be missing again. Cc: stable(a)vger.kernel.org Fixes: 1c9e16b73166 ("staging: vc04_services: vchiq_arm: Split driver static and runtime data") Signed-off-by: Javier Carrasco <javier.carrasco.cruz(a)gmail.com> --- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 27ceaac8f6cc..792cf3a807e1 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -1332,7 +1332,8 @@ MODULE_DEVICE_TABLE(of, vchiq_of_match); static int vchiq_probe(struct platform_device *pdev) { - struct device_node *fw_node; + struct device_node *fw_node __free(device_node) = + of_find_compatible_node(NULL, NULL, "raspberrypi,bcm2835-firmware"); const struct vchiq_platform_info *info; struct vchiq_drv_mgmt *mgmt; int ret; @@ -1341,8 +1342,6 @@ static int vchiq_probe(struct platform_device *pdev) if (!info) return -EINVAL; - fw_node = of_find_compatible_node(NULL, NULL, - "raspberrypi,bcm2835-firmware"); if (!fw_node) { dev_err(&pdev->dev, "Missing firmware node\n"); return -ENOENT; @@ -1353,7 +1352,6 @@ static int vchiq_probe(struct platform_device *pdev) return -ENOMEM; mgmt->fw = devm_rpi_firmware_get(&pdev->dev, fw_node); - of_node_put(fw_node); if (!mgmt->fw) return -EPROBE_DEFER; --- base-commit: d61a00525464bfc5fe92c6ad713350988e492b88 change-id: 20241013-vchiq_arm-of_node_put-60a5eaaafd70 Best regards, -- Javier Carrasco <javier.carrasco.cruz(a)gmail.com>

8 months, 3 weeks

5
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[PATCH 0/2] s390: two bugfixes (for kunit)

by Thomas Weißschuh

When trying to use kunit for s390 with ./tools/testing/kunit/kunit.py run --arch=s390 --kunitconfig drivers/base/test --cross_compile=$CROSS_COMPILE I ran into some bugs. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Thomas Weißschuh (2): s390/sclp: deactivate sclp after all its users s390/sclp_vt220: convert newlines to CRLF instead of LFCR drivers/s390/char/sclp.c | 3 ++- drivers/s390/char/sclp_vt220.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) --- base-commit: 6485cf5ea253d40d507cd71253c9568c5470cd27 change-id: 20241014-s390-kunit-47cbc26a99e6 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

8 months, 3 weeks

3
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[PATCH] staging: vchiq_arm: Utilize devm_kzalloc in the probe() function

by Umang Jain

The two resources, 'mgmt' and 'platform_state' are currently allocated dynamically using kzalloc(). Unfortunately, both are subject to memory leaks in the error handling paths of the probe() function. To address this issue, use device resource management helper devm_kzalloc() for proper cleanup during allocation. Cc: stable(a)vger.kernel.org Fixes: 1c9e16b73166 ("staging: vc04_services: vchiq_arm: Split driver static and runtime data") Signed-off-by: Umang Jain <umang.jain(a)ideasonboard.com> --- .../staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 29e78700463f..373cfdd5b020 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -285,7 +285,7 @@ vchiq_platform_init_state(struct vchiq_state *state) { struct vchiq_arm_state *platform_state; - platform_state = kzalloc(sizeof(*platform_state), GFP_KERNEL); + platform_state = devm_kzalloc(state->dev, sizeof(*platform_state), GFP_KERNEL); if (!platform_state) return -ENOMEM; @@ -1344,7 +1344,7 @@ static int vchiq_probe(struct platform_device *pdev) return -ENOENT; } - mgmt = kzalloc(sizeof(*mgmt), GFP_KERNEL); + mgmt = devm_kzalloc(&pdev->dev, sizeof(*mgmt), GFP_KERNEL); if (!mgmt) return -ENOMEM; @@ -1402,8 +1402,6 @@ static void vchiq_remove(struct platform_device *pdev) arm_state = vchiq_platform_get_arm_state(&mgmt->state); kthread_stop(arm_state->ka_thread); - - kfree(mgmt); } static struct platform_driver vchiq_driver = { -- 2.45.2

8 months, 3 weeks

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